

# 1 1 2 3 5 8 13
# 求第n项
def a(n):
    a=1
    b=1
    for i in range(n-2):
       a, b = b, a+b
    return b

def b(n):
    if n==1 or n==2:
        return 1
    else:
        return b(n-2)+b(n-1)

print(b(7), a(7))


